Optical connector connecting apparatus and optical connector connecting method

ABSTRACT

Disclosed is an optical connector connecting apparatus. In the apparatus, a plurality of fixed optical connectors are mounted on a fixed member in a lined-up manner. An optical connector containing member having a movable optical connector mounted thereon is supported on a support member through a small-diameter beam. A moving plate mounted on a base supports the support member, and the movable optical connector is moved in X-axis, Y-axis and Z-axis directions so as to be connected to the fixed optical connector. Therefore, a position deviation at the time of the connection is corrected by the flexing of the small-diameter beam so that fine-positioning is unnecessary.

This is a continuation of application Ser. No. 07/977,961, filed on Nov.18, 1992, which was abandoned upon the filing hereof.

BACKGROUND OF THE INVENTION

The present invention relates to an optical connector connectingapparatus which is excellent in reproducibility of a connection loss tobe measured, and is used for the connection of a multi-core opticalconnector having guide pins. Also, the invention relates to an opticalconnector connecting apparatus and an optical connector connectingmethod in which an optical path switching, excellent in reproducibility,is effected.

Conventionally, for measuring a connection loss of an optical connector,a pair of optical connectors 61 and 62 are guided through guide pins 64as shown in FIG. 14, and are connected together, and then as shown inFIG. 15, these connectors 61 and 62 thus connected are fixed together bya resilient clip 63. With this connection method, however, the fixing bythe clip 63 must be done manually, so that much labor and time have beenrequired, and another drawback is that the reproducibility of themeasured value has been poor.

Therefore, in order to overcome these drawbacks, there have beenproposed connection apparatuses, using a general-purposed robot or anX-Y-Z stage movable in three axes directions.

The above-mentioned connecting apparatuses using the robot or the X-Y-Zstage are of such a construction that optical connectors are connectedby guide pins or a ferrule, and therefore the positioning of the guidepins must be done with a high precision on the order of not more than amicron. Therefore, much labor and time have been required for thepositioning, and besides the positioning control mechanism has becomebulky, which has disadvantageously resulted in high costs.

Further, the connecting surfaces of the optical connectors have finedepressions and projections, and it is possible that when theseconnectors are connected together, a gap on the order of 0.1 μm toseveral tens of μm will be formed between optical fiber cores of theconnectors. Therefore, in order to prevent a deterioration of aconnection loss and reflection characteristics which are caused by thisgap, it is a common practice to fill this gap with a matching agentwhich matches the refractive index with the optical fiber core. Thematching agent is manually applied to connecting surfaces, using anapplicator 65 as shown in FIG. 16 or a toothpick. However, much laborand time have been required for such a manual application of thematching agent.

SUMMARY OF THE INVENTION

With the foregoing in view, it is an object of the invention to providean optical connector connecting apparatus which provides a goodreproducibility of connection, and does not require a complicatedcontrol mechanism.

In order to achieve this object, there must be provided the type ofconstruction in which the connection surfaces of a pair of opposed fixedand movable optical connectors to be connected together can bepositively brought into intimate contact with each other using guidepins or a ferrule. Here, assuming that the connection surfaces aredisposed perpendicular to the guide pins or the ferrule, there are twokinds of deviations of the guide pin or the ferrule from its matingfitting hole, that is, the deviation due to a parallel movement and thedeviation due to the rotation or the bending.

On the other hand, it is possible to support the movable opticalconnector by a mechanical element, such as a linear guide and a ballbearing, so that this connector can be stably connected to the fixedoptical connector. However, if such a mechanism is used, the rigidity ofthe moving mechanism must be increased, and this would increase theforce required for the driving, and as a result the apparatus wouldbecome bulky, and there is a possibility that the optical connectorwould be damaged unless the driving force is not suitably controlled.Therefore, it is necessary to provide an arrangement in which adisplacement of several tens to several hundreds μm is enabled by afollowing force of about several hundreds grams.

Further, for continuously checking a plurality of optical connectors, itis difficult, because of limited time, to precisely effect a positionadjustment in accordance with the position of each fixed opticalconnector each time each fixed optical connector is checked. Besides,the amount of displacement (commonly called "offset") between theconnected movable and fixed connectors varies depending on thecombination.

The present invention provides an optical connector connecting apparatusincluding a first optical connector fixedly supported on a body of theapparatus; a second optical connector movably supported on the apparatusbody, the second optical connector being moved to be connected to thefirst optical connector; and an elastic member for mediating between oneof the optical connectors and the apparatus body, wherein a connectionloss or reflection produced by a connection of the optical connectors ismeasured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a basic construction of a firstembodiment of the present invention;

FIG. 2 is a diagram explanatory of the relation between a force and aposition of a small-diameter beam in the first embodiment of the presentinvention;

FIGS. 3(a) and 3(b) are diagrams each explanatory of a displacement ofan optical connector and an optical connection loss in the firstembodiment of the invention;

FIGS. 4(a) and 4(b) are diagrams each explanatory of a displacement ofan optical connector and an optical connection loss in the prior art;

FIGS. 5(a) and 5(b) are perspective views of a second embodiment of theinvention, each showing an optical connector and its surroundings;

FIGS. 6(a) and 6(b) are side-elevational views of a third embodiment ofthe invention, each showing an optical connector and its surroundings;

FIG. 7 is a perspective view of a fourth embodiment of the invention,showing optical connectors, a support blocks and the surroundingsthereof;

FIG. 8 is a perspective view showing a basic construction of a fifthembodiment of the present invention;

FIG. 9(a) is a vertical cross-sectional view showing a matching agentcoating mechanism in the fifth embodiment;

FIG. 9(b) is a view taken along the line 9b--9b of FIG. 9(a);

FIG. 10 is a procedure of an operation program of the connection of anoptical connector in the embodiment of the invention;

FIG. 11 is a diagram showing the difference in connectioncharacteristics between the case where the matching agent is applied andthe case where the matching agent is not applied;

FIG. 12(a) is a vertical cross-sectional view of a matching agentcoating mechanism in a sixth embodiment of the invention;

FIG. 12(b) is a view taken along the line 12b--12b of FIG. 12(a);

FIG. 13 is a vertical cross-sectional view of a matching agent coatingmechanism in a seventh embodiment of the invention;

FIG. 14 is a perspective view of conventional optical connectors;

FIG. 15 is a perspective view of the conventional optical connectors inits connected condition; and

FIG. 16 is a perspective view showing the manner of coating a matchingagent to the conventional optical connectors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of an optical connector connecting apparatus of thepresent invention is shown in FIGS. 1 to 4, and this embodiment will nowbe described with reference to these Figures.

FIG. 1 shows a basic construction of the first embodiment. As shown inthis Figure, a plurality of fixed optical connectors (first opticalconnectors) 1 are mounted on fixed members 3 in a lined-up manner. Amovable optical connector (second optical connector) 2 is mounted on anoptical connector containing member 4 in opposed relation to the fixedoptical connectors 1. The optical connector containing meter 4 isfixedly secured through a small-diameter beam (elastic member) 6 (1.5 mmin diameter in this embodiment) to a support member 7 on an apparatusbody 10.

On the other hand, a support bed 12 is supported on a base 11 through aball thread 13 and guide shafts 14 so as to move in an X-axis direction,the base 11 constituting part of the apparatus body 10. An X-axis motor15 mounted on the base 11 rotates the ball thread 13 to move the supportbed 12 in the X-axis direction.

A moving plate 22 is supported on the support bed 12 through a ballthread 23 and guide shafts 24 so as to move in a Y-axis directionperpendicular to the X-axis direction. A Y-axis motor 25 mounted on thesupport bed 12 rotates the ball thread 23 to move the moving plate 22 inthe Y-axis direction.

Further, the above-mentioned support member 7 is supported on the movingplate 22 through a ball thread 33 and guide shafts 34 so as to move in aZ-axis direction perpendicular to the X-axis direction and the Y-axisdirection. A Z-axis motor 35 mounted on the moving plate 22 rotates theball thread 33 to move the support member 7 in the Z-axis direction.

Namely, the apparatus is constituted by the support member 7, the base11, the ball threads 13, 23 and 33, the guide shafts 14, 24 and 34, themotors 15, 25 and 35 and so on, and the apparatus body 10 serving as theX-Y-Z stage movably supports the movable optical connector 2 through thesmall-diameter beam 6.

Next, the measurement of an optical attenuation of the fixed opticalconnector 1 by the optical connector connecting apparatus of the aboveconstruction will now be described.

The motors 15, 25 and 35 on the apparatus body 10 are driven under aservo control to move the support member 7 to a prescribed address inthe sequence of the X-axis, the Y-axis and the Z-axis. The movableoptical connector 2 supported through the small-diameter beam 6 ispositioned, and is connected to the fixed optical connector 1 to measurethe amount of the optical attenuation.

Thus, the movable optical connector 2 is mounted on the support member 7through the small-diameter beam 6, and therefore when the aboveconnection is to be effected, the connector 2 is sufficiently displacedwith a small force, following the opposed fixed optical connector 1, sothat the good connection can be achieved. When the connection is to bereleased by returning the support member 7 toward the movable plate 22,the restraint by the fixed optical connector 1 is released, and thesupport member is returned to the neutral position by the elasticity ofthe small-diameter beam 6.

Namely, at the distal end portion of the small-diameter beam 6, therelation between the force and the displacement is generally linear asshown in FIG. 2, and there are provided the characteristics withoutnormal and reverse hysteresis, and a displacement of 0.4 mm or more isproduced with a force of 1 kg.

FIGS. 3(a) and 3(b) show the dependency of the connection loss on thedisplacement amount in this embodiment. FIG. 3(a) shows the relationbetween the connection loss and the displacement in the X-axisdirection, and FIG. 3(b) shows the relation between the connection lossand the displacement in the Y-axis direction. On the other hand, FIGS.4(a) and 4(b) show a similar relation in connection with a comparativeexample, and show the relation between the displacement and the opticalconnection loss in the case where a movable optical connector is mountedwithin a box-like container with a gap. In FIGS. 4(a) and 4(b), theconnection loss greatly varies, and therefore the position dependency inthe X-axis and Y-axis directions can not be read, and from the viewpoint of the reproducibility the effect achieved by the construction ofthe embodiment of the present invention has become clear from theseFigures.

Next, a second embodiment of the present invention is shown in FIGS.5(a) and 5(b), and this embodiment will now be described with referenceto this Figure. An apparatus body used here is the same as that used inthe first embodiment, and explanation thereof will be omitted.

In FIG. 5(a ), two small-diameter beams 46a of a cylindrical shape aredisposed parallel to each other, and are interposed between a supportmember 7 and an optical connector containing member 4, and a movableoptical connector 2 is supported through the two small-diameter beams46a. In FIG. 5(b), four small-diameter beams 46b are disposed parallelto one another, and are interposed similarly. Therefore, the movableoptical connector 2 properly corrects a position deviation through theflexing of the small-diameter beams 46a or 46b.

Next, FIGS. 6(a) and 6(b) show a third embodiment of the presentinvention, and this embodiment will now be described with reference tothis Figure. Explanation of an apparatus body will be omitted as in theabove embodiment.

In FIG. 6(a), although there is provided a single small-diameter beam56a, it has a reduced-diameter portion 58a intermediate the oppositeends thereof. In FIG. 6(b), similarly, there is provided a singlesmall-diameter beam 56b, and that portion of this beam intermediate theopposite ends thereof is progressively narrow. Therefore, a movableoptical connector 2 properly corrects a position deviation through theflexing of the small-diameter beam 56a or 56b of such a shape.

Next, FIG. 7 shows a fourth embodiment of the present invention, andthis embodiment will now be described with reference to this Figure.Explanation of a lower portion of an apparatus body 10 will be omittedas in the foregoing.

As shown in FIG. 7, a support member 7 is supported on a moving plate 22through a ball thread 33 and guide shafts 34 so as to move in a Z-axisdirection, and the ball thread 33 is rotated by a Z-axis motor 35mounted on the moving plate 22. Further, a support block 9 is mounted onthe support member 7 through a coil spring (spring member) 8, and anoptical connector containing member 4 is mounted on the support block 9through a small-diameter beam 6. Therefore, a spring force can beproduced in the Z-axis direction which is the connection axis direction.A movable connector 2 is fixedly mounted on the optical connectorcontaining member 4.

In the above construction, when the movable optical connector 2 is to beconnected to a fixed optical connector 1 by driving the Z-axis motor 35,a predetermined urging pressure is produced by the resiliency of thecoil spring 8, and the measurement of a loss amount can always beeffected in a stable manner.

In the above embodiments, although the optical attenuation amount ismeasured using the movable optical connector as the measurement-sideoptical connector whereas the fixed optical connector is used as thelight source-side connector, this may be reversed, that is, the movableoptical connector may be the light source-side one whereas the fixedoptical connector may be the measurement-side one.

In the optical connector connecting apparatuses of the presentinvention, the optical connector is mounted on the apparatus bodythrough the flexible member such as the elastic member, and as a resultwhen the optical connectors are to be connected together, such opposedoptical connectors are suitably brought into agreement with each otherto be connected together. Therefore, the reproducibility of theconnection loss amount is excellent, and besides the need for a finepositioning mechanism which would make the apparatus complicated isobviated. Therefore, the automatic measurement apparatus can be easilyproduced.

Continuously, a fifth embodiment of an optical connector connectingapparatus of the present invention is shown in FIGS. 8 to 11, and thisembodiment will now be described with reference to these Figures. Theoptical connector connecting apparatus in this embodiment is the same inconstruction as that in the first embodiment shown in FIG. 1, except forthe provision of a matching agent coating mechanism 20. Therefore,explanation of the same portions as those in the first embodiment willbe omitted.

In FIG. 8, the matching agent coating mechanism 20 is mounted on a base11 in parallel relation to fixed members 3, and therefore the matchingagent coating mechanism 20 faces the connecting surface of a movableoptical connector 2.

As shown in FIGS. 9(a) and 9(b), in the matching agent coating mechanism20, a pair of insertion holes 42 for respectively receiving guide pins64 are formed in a lower portion of a case 40 which has at its upperportion a tank 41 for holding the matching agent. An outlet 43 is alsoformed in this lower portion, and is disposed between the insertionholes 42. The outlet 43 is connected to the tank 41 by an introductionpassage 44, part of the introduction passage 44 intersects the insertionholes 42. A pair of plunger-like pins 45 are provided in registryrespectively with the insertion holes 42. A spring 46 wound around thepin 45 normally urges a generally conically-shaped head of the pin 45toward the outlet 43 to close the introduction passage 44. Therefore,the pins 45 and the springs 46 constitute the opening and closing means.

The movable optical connector 2 approaches the case 40, and the guidepins 64 are inserted respectively into the insertion holes 42, so thatthe movable optical connector is abutted against the case 40. As aresult, the pins 45 are retracted to open the introduction passage 44,and the matching agent is applied from the outlet 43 to be coated to theconnecting surface 2a of the movable optical connector 2.

Next, reference is now made to the switching of the optical paths of thefixed optical connectors by the optical connector connecting apparatusof the above construction.

The apparatus body 10 is driven under a servo control of the motors 15,25 and 35 to move the support member 7 in the sequence of the X-axis,the Y-axis and the Z-axis. The movable optical connector 2 supportedthrough the small-diameter beam 6 is positioned, and is connected to thefixed optical connector 1, thereby switching the optical path.

At this time, the movable optical connector 2, instructed to beconnected to a selected one of the fixed optical connectors 1, is firstabutted against the matching agent coating mechanism 20 disposed inopposed relation to the movable optical connector 2, and the matchingagent is coated to the end face of the movable optical connector 2. Themovable optical connector 2 is abutted against the matching agentcoating mechanism 20 either each time the instruction to connect themovable optical connector 2 to the fixed optical connector 1 isproduced, or each time per they are connected a predetermined number (N)of times.

FIG. 10 shows one example of operation program with respect to anoptical connector connecting method of the present invention, and theoperation will be described with reference to this Figure.

As shown in FIG. 10, when the operation is started, the number of thefixed optical connector 1, as well as the connection, is instructed inStep S1. In Step S2, a required number of connections is recalled fromthe memory whenever the power switch is turned on.

In Step S3, the X-, Y- and Z-direction addresses of the fixed opticalconnector 1 to be connected are called, and the target position isconfirmed.

In Step S4, the present connection number is judged, and if theconnection number is not 0 or an integral multiple of N, the programshifts to Step S6. If the connection number is 0 or an integral multipleof N, the program shifts to Step S5.

In Step S5, a matching agent coating instruction is produced, and themovable optical connector 2 is moved in the sequence of the X-axis, theY-axis and the Z-axis, and the guide pins 64 are inserted into theinsertion holes 42 in the matching agent coating mechanism 20, so thatthe matching agent is coated onto the connecting surface 2a of themovable optical connector 2. Then, the movable optical connector 2 iswithdrawn, and is returned to the initial position.

In Step S6, an instruction for the connection to the fixed opticalconnector 1 is produced, the movable optical connector 2 is moved in thesequence of the X-axis, the Y-axis and the Z-axis relative to the fixedoptical connector to be connected, and is connected thereto. Then, inthis condition, signals are sent to effect various measurements. Insteadof the sequential motion from X to Z in Step S5 or S6, a parallel motionof X and Y can be employed for the purpose of time-saving. In the lattercase, Z motion should be independent to avoid the damage of guide pinsand the connectors.

In Step S7, the count of a connection number counter is incremented one,and in Step S8, it is judged whether or not this connection numberreaches the predetermined number. If this result is "NO", the programreturns to Step S1, and if this result is "YES", the program isfinished.

Next, results of tests for confirming the effect of the above opticalconnector connecting method and apparatus are shown in FIG. 11, and thiswill be explained with reference to this Figure.

Referring to the conditions here, the case where the matching agent isnot applied at all is a condition A. The case where the matching agentis applied each time the connection is effected is a condition B. Thecase where the matching agent is applied each time the connection iseffected 10 times is a condition C. The case where the matching agent isapplied each time the connection is effected 50 times is a condition D.In each case, the connection loss of the optical connector, as well asreflection characteristics thereof, was measured. As a result, as shownin FIG. 11, it has been confirmed that the characteristics in theconditions B and C are excellent.

Next, a sixth embodiment of an optical connector connecting apparatus ofthe present invention is shown in FIGS. 8, 10, 11, 12(a) and 12(b), andthis embodiment will now be described with reference to these Figures.Those portions identical to those of the fifth embodiment will bedesignated by identical reference numerals, respectively, and arepetition of the explanation is omitted.

As shown in FIGS. 12(a) and 12(b), a cylinder 57, having a piston 55urged left by a spring 56, is formed in a lower portion of a case 50 ofa matching agent coating mechanism 20 which has at its upper portion atank 51 for holding a matching agent. The tank 51 is communicated via avalve 58 with the space in the cylinder 57, and the valve 58 is openedand closed by the reciprocal movement of the piston 55 in right and leftdirections. There is provided an introduction passage 54 extending fromthe space of the cylinder 57 to an opening 53 disposed midway betweeninsertion holes 52, and the matching agent is forced from the space ofthe cylinder 57 into the introduction passage 54 by the reciprocalmovement of the piston 55, so that the matching agent is discharged fromthe opening 53.

Therefore, the movable optical connector 2 approaches the case 50, andthe guide pins 64 are inserted respectively into the insertion holes 52,so that the movable optical connector 2 is abutted against the case 50.As a result, the piston 55 is moved right, so that the matching agentflows out of the case 50 to deposit on the connecting surface 2a of themovable optical connector 2. When the guide pins 64 are withdrawn fromthe insertion holes 52, the spring 56 is urged left, and therefore thepiston 55 is moved, and at the same time the valve 58 is opened toreplenish the cylinder 57 with the matching agent.

Next, a seventh embodiment of an optical connector connecting apparatusof the present invention is shown in FIGS. 8, 10, 11 and 13, and thisembodiment will now be described with reference to these Figures. Thoseportions identical to those of the fifth embodiment will be designatedby identical reference numerals, respectively, and a repetition of theexplanation is omitted.

As shown in FIG. 13, a swelling cloth 73 is supported on an outerperipheral surface of a tank 71 of a matching agent coating mechanism 20which holds a matching agent. The lower end portion of the swellingcloth 73 is dipped in the matching agent. A pair of insertion holes 72for respectively receiving the guide pins 64 are formed in the upperportion of the tank 71 in such a manner that the swelling cloth 73 isdisposed between these insertion holes 72. Therefore, when the movableoptical connector 2 is abutted against the swelling cloth 73 with theguide pins 64 inserted in the insertion holes 72, the matching agentimpregnated in the swelling cloth 73 by a surface tension is applied tothe connecting surface of the movable optical connector 2.

In the above description, although the guide pins 64 of the movableoptical connector 2 push the plunger-like pins 45 or the piston 55, thepart for pushing these pins 45 and piston 55 are not limited to theguide pins 64, and any part connected to the movable optical connector 2may be used for this purpose.

In the optical connector connecting apparatus according to the presentinvention, the matching agent is provided between the connectingsurfaces when the optical connectors are connected together, andtherefore the connection loss amount is reduced, and the finepositioning mechanism which makes the apparatus construction complicatedbecomes unnecessary.

What is claimed is:
 1. An optical connector connecting apparatuscomprising:a first optical connector fixedly supported on a body of saidapparatus; a second optical connector movably supported on the apparatusbody, an elastic member having first and second ends, said first endbeing coupled to said second optical connector, means coupled to saidsecond end of said elastic member for moving said elastic member andthus said second optical connector in three spatial planes so as toconnect said second optical connector to said first optical connector;whereby a connection loss due to displacement of the second opticalconnector in at least two of the spatial planes is minimized.
 2. Theoptical connector connecting apparatus according to claim 1, whereinsaid elastic member includes a beam which has flexibility and has anarrow, elongate shape, said second optical connector being mounted andsupported on a distal end of said beam.
 3. The optical connectorconnecting apparatus according to claim 2, wherein said beam varies incross-sectional shape in its longitudinal direction.
 4. The opticalconnector connecting apparatus according to claim 1, wherein saidelastic member includes a plurality of beams which have flexibility andhave a narrow, elongate shape, said second optical connector beingmounted and supported on distal ends of said beams.
 5. An opticalconnector connecting apparatus comprising:a first optical connectorfixedly supported on a body of said apparatus; a second opticalconnector movably supported on the apparatus body, said second opticalconnector being moved to be connected to said first optical connector;an elastic member for mediating between one of said optical connectorsand the apparatus body; and a spring member producing a spring force ina direction of the axis of connection of said one optical connector isprovided between said one optical connector and the apparatus body,wherein a connection loss, produced by a connection of said opticalconnectors is measured.